I am trying to wire A/C into my VEMS from BMW E36 M50B30. Stock relies on pressure sensor to trip compressor relay. I can wire the two together and it works but I would like to utilize VEMS N2O output to control based upon TPS, MAP etc.
The compressor relay is fine to wire to p259 from an amperage standpoint but I am not sure about the pressure sensor.
When off, it shows full system voltage - when it receives power from A/C cabin button it draws ~.2 Amp and has a voltage of around .45 Volts
I know the current side of the sensor is fine for a p259 channel (< 300 mA), but when it is off (that is A/C cabin button is off) it has +12v. Can the sensor be hooked up to a p259 or must I sacrifice my last ignition output (that I am saving for boost control)?
I know I have seen something similar regarding fuel pump relays - that when off you see system voltage or something to that effect but I want to confirm whether or not +12v there will kill the board?
May seem simple, but I am not terribly well versed with this type of thing - if anyone has any input I would really appreciate it.
Thanks!
